1. Technical Field
The present invention relates to a vibrating element, a vibrator, an electronic apparatus, and a moving object.
2. Related Art
In the related art, for example, angular velocity sensors (vibration gyro sensors) that detect a physical quantity such as an angular velocity or an acceleration and are used for body control in vehicles, self-position detection of car navigation systems, vibration control correction (so-called camera-shake correction) for digital cameras or video camcorders, or the like have been known.
In an angular velocity sensor including a vibrating element called an “H type” including a pair of drive vibrating arms and a pair of detection vibrating arms, the drive vibrating arms flexurally vibrate (drive-vibrate) close to or away from each other by energization. In this state, when an angular velocity about a predetermined axis is applied to the angular velocity sensor, the drive vibrating arms flexurally vibrate in opposite directions with the Coriolis force, and consequently, the detection vibrating arms flexurally vibrate (detection-vibrate) in opposite directions. With the detection vibrations of the detection vibrating arms, charge is generated at electrodes provided on the detection vibrating arms. By detecting the charge, the angular velocity applied to the angular velocity sensor can be obtained.
In such an angular velocity sensor, adjustments of frequencies such as the resonance frequency of drive vibration of the drive vibrating arm, the resonance frequency of detection vibration of the detection vibrating arm, and a detuning frequency as a difference between the resonance frequency of the drive vibration and the resonance frequency of the detection vibration are carried out for preventing variations in the frequencies of products after manufacture (for example, refer to Japanese Patent No. 4107768). For example, the adjustment of the detuning frequency is carried out by changing the mass of the drive vibrating arm or the detection vibrating arm by providing a weight on the drive vibrating arm or the detection vibrating arm, or removing a portion of the provided weight. The resonance frequency of drive vibration of the drive vibrating arm is moved away from the resonance frequency of detection vibration of the detection vibrating arm for the reason that if they are proximate to each other, noise is introduced into signals output from the angular velocity sensor due to the influence of the drive vibration of the drive vibrating arm.
However, in the angular velocity sensor in the related art, the amount of change in detuning frequency per unit mass is small. For this reason, the mass of the drive vibrating armor the detection vibrating arm needs to be greatly changed to bring the detuning frequency to a target value, which involves a problem of disturbing the balance of the drive vibrating arm or the detection vibrating arm and thus deteriorating characteristics.